The present disclosure relates to an optical sheet.
Cathode ray tubes (CRTs) are used in larger electronic devices, such as televisions, monitors for measuring devices, and other information terminals. However, the innate weight and size of CRTs are incompatible with smaller electronic devices.
Typically, liquid crystal display (LCD) devices are lighter, thinner, and smaller than CRTs. A LCD generally consumes less power than CRTs. Thin-film transistor (TFT) LCD devices may provide full color, high resolution, and a large display screen size. Accordingly, TFT LCD devices are used in a wide range of electronic devices, such as laptop computers and monitors.
A typical LCD device is a light-receiving display device that displays an image. The LCD device uses a change in an optical characteristic of a liquid crystal cell, such as birefringence, optical rotatory power, dichroism, and light scattering, by applying a voltage to the liquid crystal.
Because the LCD device is a light-receiving device, it includes a backlight unit providing light to display an image.
The backlight unit may be a direct type backlight unit or an edge-type backlight unit depending on the location of a light source. A direct-type backlight unit uses a plurality of light sources that are disposed at regular intervals under the LCD panel to directly provide light to an LCD panel. An edge-type backlight unit uses a light guide plate that converts light emitted from a light source into surface light to provide light to an LCD panel.
The backlight unit uses optical sheets, such as a diffusion sheet and a prism sheet, to enhance the optical characteristics (e.g., brightness uniformity and front brightness) of light emitted from the light source.
An LCD device with an optical sheet may have an optical loss that degrades the optical efficiency of the LCD device.
A prism sheet includes ridges and furrows. A non-uniform brightness may be caused by abrasion of the ridges due to friction with a light guide plate or other sheets.